US3314878A - Hydrocarbon conversion for light gas production - Google Patents

Description

A ril 18, 1967 OLEFINIC FEED R. H. KOZLOWSKI 3,314,878 HYDROCARBON CONVERSION FOR LIGHT GAS PRODUCTION Filed July 29, 1964 50 I I I I so a0 CONVERSION-VOLVa BELOW c1 INVENTOR F|G.2

ROBERT KOZLOWS/(l waf Kg-1w 0 m United States Patent Ofifice 3,314,878 Patented Apr. 18, 1967 3,314,878 HYDRUCAREQN CONVERSION FOR LIGHT GAS PRUDUCTION Robert H. Kozlowslki, Berkeley, Calif, assignor to Chevron Research Company, a corporation of Delaware Filed July 29, 1964, Ser. No. 385,992 Claims. (Cl. 208-58) This invention relates to a process for the catalytic conversion of hydrocarbon distillates to light gases. More particularly, the invention relates to a catalytic conversion process for hydrocracking hydrocarbon distillates to light gases. Still more particularly, the invention relates to a combination catalytic conversion process for hydrocracking hydrocarbon distillates to light gases and for hydrogenating olefins to parafiins.

The refiner is currently faced with the problem of how to dispose of low boiling distillates, i.e., straight run gasoline fractions boiling between about P. which have no gasoline potential because of their low octane number. In many areas the refiner is also faced with a problem of disposing of large amounts of low boiling olefinic feeds. This is especially true where there is an imbalance between i-butane and butenes which are used in preparing fialkylatef In contrast, the refiner has the problem of meeting the demand for propane and n-butane used in LPG and i-butane used in preparing alkylate. V

Heretofore, the refiner has found it difiicult to achieve high yields of propane and butanes from low boiling distillates in a hydrocracking process operating at low pressures while maintaining high conversions to products boiling below the initial boiling point of the feed. In Patent 2,428,692, high yields of butanes and pentanes were obtained from a cycle stock boiling between about 290 and 470 F. only by destructively hydrogenating at high pressures and high hydrocarbon recycle rates. In addition, very low yields of propane were obtained in this destructive hydrogenation process. It would be desirable if a low-pressure process were available for hydrocracking low value distillates into higher yields of high value propane and butane gases than previously obtainable without the necessity of hydrocarbon recycle.

Heretofore, the refiner has carried out reactions for hydrocracking distillate feeds and hydrogenating olefinic feeds in separate reactors and has recovered the products from separate distillation systems. This has resulted in an uneconomical and inefiicient process. It would be desirable if an economical process were available for hydrocracking a distillate feed and hydrogenating an olefinic feed in the same reactor and recovering the combined products from a common distillation system.

It is an object of the present invention to provide a process for hydrocracking a low boiling hydrocarbon distillate feed and hydrogenating a low boiling olefinic feed on a once-through basis at low pressures in the same reactor and recovering the products from a common distillation system.

This invention will be more clearly understood and further objects and advantages thereof will be apparent from the foregoing description when read in connection with the accompanying drawings, in which:

FIGURE 1 is a diagrammatic illustration of a simplified embodiment of process units and flow paths suitable for carrying out one embodiment of the present invention;

FIGURE 2 is a graphical illustration of the conversion to products boiling below the C boiling range plotted against the product yield expressed at CF04 m X 100 A preferred method of operating the process i the present invention is to contact the hydrocarbon distillate peratures in the range of about 550750 F., about 800- a once-through of said distillate feed boiling range and to contact the efiluent from said hydrocracking zone and an 1000 psig. and about basis to convert above 0.3l.0 LHSV on about 60% hydrocracking zone petroleum, gilsonite, shale and coal oil. The naphtha feeds are generally of low octane number, and hence, a low value to the refiner.

The process of the The nitrogen content of the olefinic feeds may be decreased to preferred levels by any suitable method. One method occurs a drastic reduction in conversion below C and yield as described above. As the pressure is increased from 1000 p.s.i.g. up to about 1700 p.s.i.g., there is a noticeable decrease in the conversion below C vand yield as described above. At pressures outside the range of about 800l000 p.si..g. there is also an increase in the fouling rate of the hydrocracking catalyst. The operating conditions for the hydrocracking zone also include tem- F., preferably 600-750 F., and space velocities in the range of about I through line 8 to other column not shown.

3 0.3l.0 LHSV. Below 550 F. the temperature is insufficient to convert the feed to the desired products and above 750 F. the fouling rate of the hydrocracking catalyst becomes too great to warrant further operation. By operating at such conditions, the once-through conversion in the hydrocracking zone is above about 60% to products predominantly comprising C iC and nC That is,

' oa-o.

is above about 50% and the remainder of the product is a C C high octane gasoline blending stock. The remaining Cq+ material has a higher octane number and is a better reforming feed than the original distillate.

The hydrocracking catalyst comprises a hydrogenatingdehydrogenating component such as any Group VIII metal, preferably platinum or sulfides of nickel and/ or cobalt intimately associated with a solid, active, acidic cracking component. The active, acidic component may comprise any of the conventional cracking catalysts such as silica-alumina, silica-alumina-zirconia, acid-treated clays and the like. A preferred active, acidic component for use in the hydrocracking catalyst of the present invention is comprised of synthetically prepared silicaaluminas having silica contents in the range of from about 70 to 99%. The total amount of hydrogenating-dehydrogenating component can vary from about 0.1- weight percent (calculated as metal) of the catalyst composition. It has been found that hydrocracking catalysts having metal levels above this range foul at an excessive rate when used in the process of the present invention. The hydrocracking catalyst of the present invention may be prepared in a manner as set forth in Patent No. 2,944,006.

The hydrogenation zone operating conditions include at least about 1000 s.c.f. hydrogen/bbl. of olefinic feed, an LI-ISV from about 0.1-10, pressures in the range of about 800 to 1000 p.s.i.g., and temperatures in the range of about 500775 F.

The hydrogenation catalyst comprises a hydrogenatingdehydrogenating component and a, i.e. non-acidic, cracking component. The hydrogenating component comprises at least one of the Group VI and at least one of the Group VIII metals, preferably cobalt-molybdate. The non-active cracking component comprises silica, titania, zirconia, bauxite, charcoal or alumina. The preferred hydrogenation catalyst comprises cobalt-molybdate on alumina as prepared in a manner set forth in Patent No. 2,878,193.

Referring now to FIGURE 1 there is shown a simplified schematic illustration of a preferred embodiment of process units and flow paths suitable for carrying out the process of the present invention. A distillate feed is passed through line 1 to reactor 3 where it is hydrocracked by contact with hydrocracking catalyst in zone 4 in the presence of make-up hydrogen, supplied through line 2, under suitable conditions as discussed above. A water-washed olefinic feed is passed through line 5 to reactor 3 where it is hydrogenated by contact with hydrogenation catalyst in zone 7 in the presence of make-up hydrogen, supplied through lines 2 and 6. The effluent from hydrocracking zone 4 is passed to hydrogenation catalyst zone 7. The effluent from zone 7 is passed high pressure separator 9. From high 9, hydrogen is recycled to line 10 to reactor 3 and a hydrocarbon stream is passed through line 11 to distillation column 12. Column 12 overhead is passed through line 13 to reflux drum 14. From reflux drum 14, a C fraction is removed through line 15 and a C -C fraction is removed through line 16. A portion of the C C fraction is refluxed to distillation column 12 through line 17 and the remaining portion is passed as feed to column 19 through line 18 where the C product is recovered through line 20 and C s are recovered through line 21. The C s may be separated further into an nC product and an iC product in an- A high octane C -C blendpressure separator ing stock is recovered from column 12 through line 22 and a 0 bottoms fraction is passed through line 23 to be blended with the C -C stock or passed to further processing such as catalytic reforming.

If desired, a portion of the olefinic feed may be passed through lines 24 and 1 to hydrocracking zone 4.

Referring next to FIGURE 2 there is shown a graphical illustration of the hydrocracking conversion to products boiling below the C7 boiling range as a function of the product yield expressed as The broad band between the two parallel lines represents a region in which most of the results would fall if one were to operate within the range of hydrocracking conditions of the process of the present invention. The cross-hatched section between the two solid parallel lines represents a region in which the laboratory data fell. This figure indicates that by means of one embodiment of the process of the present invention, products predominantly comprising C i0; and nC hydrocarbons can be obtained at overall conversions below C above about 60%.

Examples Table I below indicates the inspections of the various naphtha feed stocks used as feed to the hydrocracking zone in the examples below.

TABLE L-NAIIITHA FEED INSPECTIONS Feed Arabian Sumatra P Gravity, API 60. 4 61 60. 5 ASIM D-86, F., LV Percent:

E1? 313 322 355 Octane No., F4 Clear. 36. 0 36.0 F1+3 ml. TEL/gal. 58.5 62. 6 Total Nitrogen, p.p. 0. 1 0. 1 0. 27 Sulfur, p.p.m 12 1 .6 36

Example 1 TABLE II.-OPERATING CONDITIONS AND PRODUCTS YIELDS Feed North African Arabian Run No 1 2 Operating Conditions:

Pressure, p.s.i.g. 800 750 Temperature, F 680 6114 LHSV 0.3 0. 3 Total Gas Rate, s.f.c.lb 5, 960 5, 5'10 Gonversionbelow 01, LV percent. 83. 8 S2. 3 Product Yields, Wt. percent:

C 0. 06 0.03 0. 32 0. 13 1G. 6 13. 4 28. 4 28. 1 10.8 8. 7 21.0 20. 4 9. 2 l4. 1 16. 2 17. 5 55.8 50. 2 86. 0 84. 7

m Example 2 Table II below indicates the critical eifect pressure has on hydrocracking the North African naphtha feed of Table I in the presence of a NiS (6 wt. percent Ni) r and silica-alumina catalyst. Table III shows that with 0 all other conditions remaining essentially constant, there is a decrease in the conversion below C and CFCtX when the hydrocracking reaction is operated in a pressure range other than about 8004000 p.s.i.g.

TABLE III Run No 3 4 5 M Operating Conditions:

Pressure, p.s.i.g 800 500 1,100 Temperature, F- 712 719 719 LHSV 0.3 0.3 0.3 Total Gas Rate, s.e.f. I. 6,070 5,490 6,150 Conversion below 07, LV percent 87. 4 76. 6 86. 1 Product Yields, Wt. Percent:

01 0. 08 0. 07 0. 08 C2 0. 33 0.55 0.46 Ca. 17. 4 13.2 16.2 i0;- 31.1 23. 2 26.8 1 I104 13. 7 9. 7 11.6 C s 15. 6 18. 1 22. 8 CsS 7. 7 9. 0 9. 3 Total 0 -04. 62. 2 46. 1 54. 6 Total 03-0 85. 5 73. 2 86. 7

a 4 X100 72. 7 63. 0 (i3. 0 CZCG product yields obtained on hydrocracking the North African naphtha feed of Table I in the presence of a 0 5 wt. percent Pt and silica-alumina catalyst.

TABLE IV Run No 6 Operating conditions Pressure, p.s.i.g 900 Temperature, F. LHSV Conversion below C LV percent Product yields, wt. percent:

C C C 15.0 iC 20.6 110 16.5 iC 12.2 RC5 C s 9.5 Total C -C 52.1 Total 0 4:, 81.0 CF04 m X 100 64:.3

xamp e Table VI below indicates the operating conditions, product yields and product properties obtained on hydrocracking the Sumatra naphtha feed of Table I on a once- 75 6 through basis in the presence of a NiS (6 wt. percent Ni) disposed on silica-alumina. Table VI also indicates the TABLE VI Run N 0.

Zone Hydro- Zone Hydroeraeking genation M R Operating Conditions:

Pressure, p.s.i.g 750 750 Temperature, F. l 630 2 700 LHSV 0.3 1.0 Total Gas Rate, s.c.f./I 5, 700 16,800 Conversion Below 07, LV percent. 86. 3

Hydrocracking Hydroeraeking Alone with Olefin hydrogenation Product Yields, Wt. percent (Based on Naphtha feed):

0 -05 Product Properties:

Bromine No 0. 03 Octane N o. F1+3 n11. TEL/gal. 98. 5 99. 3 Cpl-Bottoms Properties:

Bromine N o 0. 07 Octane No. Fl+3 ml. TEL/gal. 77. 0

1 Average. 2 Maximum.

Although only specific embodiments of operation of the present invention have been described, numerous 60 percent of said distillate the C boiling range and feed to products boiling below predominantly comprising C iC and nC, hydrocarbons, and contacting the efliuent from said hydrocracking zone and an olefinic feed selected from the group consisting of C -C olefins in a hydrogenation zone with a hydrogenation catalyst consisting essentially of a hydrogenating-dehydrogenating component and a nonactive non-acidic cracking component seletced from the group consisting of silica, titania, zirconia, bauxite, charcoal and alumina, at operating conditions of about 500775 F., about 800-1000 p.s.i.g. and about 01-10 LHSV on a once-through basis to convert above about 90 percent of said olefinic feed to paraffins.

2. A process as in claim 1, wherein said hydrocracking catalyst comprises nickel sulfide and silica-alumina.

3. A process as in claim 1, wherein said hydrocracking catalyst comprises platinum and silica-alumina.

4. A process as in claim 1, wherein said hydrogenation catalyst comprises cobalt-molybdenum and alumina.

5. A process as in claim 1, wherein said olefinic feed is water-washed prior to contact with said hydrogenation catalyst.

6. A hydrocracking-hydrogenation process which comprises contacting an olefinic feed selected from the group consisting of C -C olefins and hydrogen in a hydrogenation zone with a hydrogenation catalyst consisting essentially of a hydrogenating-dehy-drogenating component and a nonactive non-acidic cracking component selected from the group consisting of silica, titania, zirconia, bauxite, charcoal and alumina, at operating conditions of about 500775 F., about 800-1000 p.s.i.g. and about 0.1- 10 LHSV on a once-through basis to convert above about 90 percent of said olefinic feed to paraifins and contacting 8 the effluent from said hydrogenation zone and a hydrocarbon distillate feed boiling between about 170 and 320 F. in a hydrocracking zone with a hydrocracking catalyst comprising a hydrogenating-dehydrogenating component and an active acidic cracking component compris ing a conventional cracking catalyst at operating conditions of about 550-750 F., about 800-1000 p.s.-i.g. and about 0.31.0 LHSV on a'once-through basis,ithereby converting above about percent of said distillate feed to products boiling below the C boiling range and predominantly comprising C iC, and nC hydrocarbons.

7. A process as in claim 6, wherein said hydrogenation catalyst comprises cobalt-molybdenum and alumina.

8. A process as in claim 6, wherein said olefinic feed is water-washed prior to contact with said hydrogenation catalyst.

9. A process as in claim 6, wherein said hydrocracking catalyst comprises nickel sulfide and silica-alumina.

10. A process as in claim 6, wherein said hy-drocracking catalyst comprises platinum and silica-alumina.

References Cited by the Examiner UNITED STATES PATENTS DELBERT E. GANTZ, Primary Examiner. A. RIMENS, Assistant Examiner.

Claims (1)

1. A HYDROCRACKING-HYDROGENATION PROCESS WHICH COMPRISES CONTACTING A HYDROCARBON DISTILLATE FEED BOILING BETWEEN ABOUT 170* AND 320*F. AND HYDROGEN IN A HYDROCRACKING ZONE WITH A HYDROCRACKING CATALYST COMPRISING A HYDROGENATING-DEHYDROGENATING COMPONENT AND AN ACTIVE ACIDIC CRACKING COMPONENT COMPRISING A CONVENTIONAL CRACKING CATALYST AT OPERATING CONDIIONS OF ABOUT 550*750*F., ABOUT 800-1000 P.S.I.G. AND ABOUT 0.3-1.0 LHSV ON A ONCE-THROUGH BASIS THEREBY CONVERTING ABOVE ABOUT 60 PERCENT OF SAID DISTILLTE FEED TO PRODUCTS BOILING BELOW THE C7 BOILING RANGE AND PREDOMINANTLY COMPRISING C3, IC4 AND NC4 HYDROCARBONS, AND CONTACTING THE EFFLUENT FROM SAID HYDROCRACKING ZONE AND AN OLEFINIC FEED SELECTED FROM THE GROUP CONSISTING OF C3-C6 OLEFINS IN A HYDROGENATION ZONE WITH A HYDROGENATION CATALYST CONSISTING ESSENTIALLY OF A HYDROGENATING-DEHYDROGENATING COMPONENT AND A NONACTIVE NON-ACIDIC CRACKING COMPONENT SELECTED FROM THE GROUP CONSISTING OF SILICA, TITANIA, ZIRCONIA, BAUXITE, CHARCOAL AND ALUMINA, AT OPERTING CONDITONS OF ABOUT 500*-775*F., ABOUT 800-1000 P.S.I.G. AND ABOUT 0.1-10 LHSV ON A ONCE-THROUGH BASIS TO CONVERT ABOVE ABOUT 90 PERCENT OF SAID OLEFINIC FEED TO PARAFFINS.

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